Fitness or Obesity: What Is the Major Target for Intervention?

German Diabetes MeetingStuttgart, GERMANY

May 15, 2010

Steven N. BlairProfessor

Departments of Exercise Science & Epidemiology/Biostatistics

University of South Carolina

Is too much attention given to obesity and not enough to

physical activity?

Do We Have an Epidemic of Obesity?

Global Trends in Childhood Overweight

International Obesity Taskforce. http://www.iotf.org/database/index.asp.

Global Trends in Childhood Overweight

International Obesity Taskforce. http://www.iotf.org/database/index.asp.

Global Trends in

Adult Obesity

International Obesity Taskforce. http://www.iotf.org/database/index.asp.

Causes of the Obesity Epidemic

It’s calories that count

Energy InEnergy In Energy OutEnergy Out

BMRBMRThermic effect of foodThermic effect of foodMedia (TV,PC)Media (TV,PC)CarsCarsNo heavy labourNo heavy labourExerciseExercise

Portion sizePortion sizeHigh-fat foodsHigh-fat foodsEnergy denseEnergy denseLow-fiberLow-fiberSoft drinksSoft drinksSnack foodsSnack foods

Is the Average Total Daily Caloric Intake Increasing?

Trends in Energy Intake1971 to 2000, Women, NHANES

0

500

1000

1500

2000

2500

All Ages 20-39 y 40-59 y 60-74 y

1971-741976-801988-941999-00

Kcal/day

Source: MMWR Feb 6, 2004

NHANES Survey Methods 1971-2000

• NHANES I and NHANES II– 24-hour dietary recall, Monday-Friday

• NHANES III and NHANES– 24-hour dietary recall, Monday-Sunday

• Other changes in methodology included better probing techniques and better training of interviewers

• Other changes in dietary behavior included more meals eaten away from home and increasing portion sizes

Trends in Chinese Energy Intake: Adults 18-45 years

Zhai F., Wang H., Du S., He Y., Wang Z., Ge K., Popkin B.M., Nutr Rev., 2009.

Ene

rgy

Inta

ke

(MJ)

Trends in Energy Intake in Men from Tanushimaru , Japan

Adachi H., Hino A., J Epidemiol., 2005

Ene

rgy

Inta

ke

(kca

l)

Trends in Energy Expenditure

Proportion of households with car or van ownership,

1951 to 2004, Great Britain

Department of Transport, Scottish Executive and Welsh Assembly. (2005)

Trends in Riding Lawnmower Sales in the US: 1981-2001

0

200

400

600

800

1000

1200

1400

1600

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

In thousands

Slide from L DiPietro, Stock Conference, 2002

Borodulin, K. et al. Eur J Public Health 2008 18:339-344; doi:10.1093/eurpub/ckm092

The 30-year trends of leisure time,

occupational and commuting physical

activity among Finnish adults

Occupational and Domestic PA trends in Chinese Adults, 1991-2000

Monda et al. Eur J Clin Nutr. 2008; 62: 1316-1325

Aerobics Center Longitudinal Study

Design of the ACLS1970 More than 80,000 patients 2005

Mortality surveillance to 2003More than 4000 deaths

Cooper Clinic examinations--includinghistory and physical exam, clinical tests,body composition, EBT, and CRF

1982 ‘86 ‘90 ‘95 ’99 ‘04Mail-back surveys for case finding and monitoring habits and other characteristics

All-Cause Death Rates by CRF Categories—3120 Women and

10 224 Men—ACLS

0

10

20

30

40

50

60

70

Ag

e ad

j d

eath

rat

e/10

,000

P

Y

Low Moderate High

Women

Men

Blair SN. JAMA 1989

Amount of Specific Physical Activities for Moderately Fit Women and Men

• Detailed physical activity assessments in women and men who also completed a maximal exercise test

• Average min/week for the moderately fit who only reported each specific activity

0

20

40

60

80

100

120

140

160

Women Men

Walk

Aerobics

Run

Mean Min/week

N=3,972 13,444Stofan JR et al. AJPH 1998; 88:1807

Fitness, Fatness, and Health

Interrelationships Among the Twin Epidemics of Obesity,

Low Fitness, and Health

Activity/Fitness

Obesity/Fat Distribution

Morbidity orMortality

No grants should be awarded nor papers publishedon fitness or obesity, and a health outcome unless both exposures are accurately measured and taken into account in analyses

Cardiorespiratory Fitness, BMI, and Mortality, ACLS Men• 25,389 men followed 8.5 years

• 673 deaths in 212,364 MY

• Cardiorespiratory fitness assessed by a maximal exercise test

• Calculated age-adjusted death rates for BMI and fitness categories

Barlow et al. Int J Obes 1995; 19:Suppl 4, S41-4

Age-Adjusted Death Rates by Fitness and BMI Categories

0

10

20

30

40

50

60

70

<27 27-30 >30

Low fit

Mod fit

High fit

# deaths 133 189 119 63 67 17 75 19Man-Yrs 25,537 64,103 57,004 15,000 20,749 7,341 14,301 8,240

Deaths/10,000 MY

Barlow et al. Int J Obes 1995; 19:Suppl 4, S41-4

Results held after adjustment for health status, smoking, glucose,

cholesterol, & BP

Criticisms of 1995 Int J Obes Study on Fitness & Fatness

• “What a lot of rubbish”• Findings counter to “what we know”• Fit men with a high BMI were not fat, but

had a high level of muscular development

• Category of low fit men with a low BMI had an excess of smokers

• Statistical adjustment for health status did not remove confounding by chronic disease

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Adj RR*

<17 17-25 >25 <17 17-25 >25

Fit

Unfit

All-cause Mortality CVD Mortality

*adjusted for age, exam year, smoking, alcohol, & parental historyLee CD, Blair SN, & Jackson AS. Am J Clin Nurt 1999; 69:373-80

RR for All-cause and CVD Mortality in Fit and Unfit

ACLS Men by Body Fat Categories

Body Fat%

Body Fat%

Adjusted RR for All-Cause Mortality by Fitness and Waist Circumference

• Waist circumference measurements in a subgroup 14,043 men

• 162 deaths in 78,008 man-years

• RR adjusted for age, examination year, smoking habit, alcohol intake, and parental history of CHD

00.5

11.5

22.5

33.5

44.5

5

Adj RR

Low Moderate High

Waist Circumference (cm)

Fit

Unfit

<87 87-<99 99

Lee CD, Blair SN, & Jackson AS. Am J Clin Nurt 1999; 69:373-80

Adjusted RR for All-Cause Mortality by Fitness and BMI, ACLS Women

0

0.5

1

1.5

2

2.5

3

3.5

4

Adj RR*

NormalWeight

Overweight Obese

Fit

Unfit

Farrell et al. Obes Res. 2002; 10:417-423

*adj for age, exam year,smoking, & healthstatus

Fitness, Fatness, and Mortality in Men with Type 2

Diabetes

Low Fitness and Inactivity as Mortality Predictors in Men with Diabetes

• Prospective study of 1,263 men, age=50±10 years

• All men had type 2 diabetes at baseline– FPG 126 mg/dL– history of physician-diagnosed diabetes– taking anti-diabetic medication

• Low fit=least fit 20% (42% of the men)• Inactive=no reported activity, past 3 months• Follow-up of 11.7 years, 14,777 man-years• 180 deaths (92 CVD)

Wei et al. Ann Int Med 2000; 132:605-11

RR for Mortality by Fitness Level in Men with Type2 Diabetes

R e l a t i v e R i s k ( 9 5 % C I ) *

F i t n e s s L e v e l C V D A l l - c a u s e

L o w 1 . 0 1 . 0

M o d e r a t e 0 . 4 ( 0 . 3 - 0 . 7 ) 0 . 4 ( 0 . 3 - 0 . 6 )

H i g h 0 . 3 ( 0 . 2 - 0 . 6 ) 0 . 2 ( 0 . 1 - 0 . 4 )

*Adjusted for age and examination year Wei et al. Ann Int Med 2000; 132:605-11

RR* for All-Cause Mortality by Fitness and BMI Levels in Men with Type 2

DiabetesF i t n e s s R R ( 9 5 % C I ) * B M I R R ( 9 5 % C I ) *

L o w 1 . 0 < 2 5 . 0 1 . 0

M o d e r a t e 0 . 4 ( 0 . 3 - 0 . 6 ) 2 5 . 0 - 2 9 . 9 1 . 2 ( 0 . 8 - 1 . 7 )

H i g h 0 . 2 ( 0 . 1 - 0 . 4 ) 3 0 + 1 . 3 ( 0 . 9 - 1 . 9 )

*Adjusted for age and examination year

Wei et al. Ann Int Med 2000; 132:605-11

RR for All-Cause Mortality in Low Fit Men with Type 2 Diabetes, Adjusted for Age and

Exam Year

00.5

11.5

22.5

33.5

4 Yes

No

Adj R R

BMI25 High Chol Baseline CVD Known Diab High BP Smoker Parental CVDReference Category (RR=1.0) is fit men

Wei et al. Ann Int Med 2000; 132:605-11

95% CI >1.0 for all analyses

CVD Mortality Risk* by Fitness and BMI Categories, 2316 Men with Diabetes,

179 CVD Deaths

0

1

2

3

4

5

6

7

8

9

10

Ris

k o

f C

VD

Mo

rta

lity

18.5 < BMI <25.0 25.0 ≤ BMI <30.0 30.0 ≤ BMI < 35.0

Re

fere

nc

e

Church TS et al. Arch Int Med 2005; 165:2114*Adj for age and examination year

p for trend <0.0001p for trend <0.0001 p for trend <0.002

≥5 METs

<5 METs

Normal weight(n = 78)

Overweight(n = 330)

Obese(n = 423)

0.500

0.625

0.750

0.875

1.000

0.0 2.0 4.0 6.0 8.0

Su

rviv

al

0.500

0.625

0.750

0.875

1.000

0.0 2.0 4.0 6.0 8.0 0.500

0.625

0.750

0.875

1.000

0.0 2.0 4.0 6.0 8.0

Follow-up (years)Follow-up (years)

Follow-up (years)

Survival curves by fitness levels within BMI categories in 831 men with type 2 diabetes, Veterans

Exercise Testing Study (1995-2006)

McAuley et al. Diabetes Care 2007;30:1539-43Slide from P McAuley

Attributable Fractions

Attributable Fractions of Health Outcomes For Low Cardiorespiratory Fitness and

Other Predictors, ACLS

•Attributable fraction (%) is the estimated number of deaths due to a specific characteristic

•Based on strength of association•Prevalence of the condition

Attributable Fractions for All-Cause Mortality

Blair S.N., Br J Sports Med., 2009

Relative Risks and Attributable Fractions of All-Cause and CVD Mortality by BMI

Categories in Men

• 25,714 (1,025 all-cause and 439 CVD deaths) men aged ≥20 years in the ACLS.

• 10 years of follow-up.• Attributable fractions are adjusted for

age, examination year, BMI, parental history of CVD, and each other item in the table.

Wei M. et al., JAMA, 1999

Relative Risks (RR) and Attributable Fractions (AF) of All-Cause Mortality by

BMI Categories in MenNormal Overweight Obese

RR (95% CI) AF, % RR (95% CI) AF, % RR (95% CI) AF, %

Baseline CVD 2.3 (1.8-2.9) 19 2.0 (1.6-2.4) 19 2.4 (1.7-3.5) 27

Diabetes 1.3 (0.9-1.8) 2 1.6 (1.3-2.0) 6 1.5 (1.1-2.2) 9

High cholesterol

1.0 (0.8-1.3) 0 1.3 (1.1-1.6) 8 1.7 (1.2-2.3) 18

Hypertension 1.5 (1.2-1.9) 12 1.4 (1.2-1.7) 13 1.1 (0.8-1.4) 4

Current smoker

1.4 (1.1-1.8) 7 1.5 (1.2-1.9) 9 1.5 (1.0-2.1) 9

Low fitness 1.6 (1.3-2.1) 10 1.7 (1.4-2.0) 18 2.3 (1.5-3.4) 44

Wei M. et al., JAMA, 1999

Summary• Inactivity and low fitness are major

determinants of morbidity and mortality

• Patients with type 2 diabetes should be strongly advised to become and stay physically active

• More attention should be paid to regular physical activity in public health and clinical settings

Ranking of selected risk factors: 6 leading causes of death by income group, estimates for 2004

Percentage of total (total: 1.53 billion)

World Health Organization. http://www.who.int/healthinfo/global_burden_disease/global_health_risks/en/index.htm

Final Message

• Focus on

– Healthful eating habits

• Fruits and vegetables

• Whole grain

– Regular physical activity

• Three 10 minute walks/day

Thank youQuestions?